Pitch angle measuring system and method for wind turbines

Abstract

The present invention relates to a wind turbine and a measuring system for determining the pitch angle of at least one blade relative to a hub of a wind turbine. The measurement comprises a first angular-velocity sensor () measuring a first angular velocity (φ) around a first sensor axis (e), the first angular-velocity sensor () fixedly attached to the at least one blade () with a first predetermined orientation selected to produce a first projection of the main rotational axis () onto the first sensor axis (e), a second angular-velocity sensor () measuring a second angular velocity (β) around a second sensor axis (e), the second angular-velocity sensor () fixedly attached to the at least one blade () with a second predetermined orientation selected to produce a second projection of the main rotational axis () onto the second sensor axis (e), the first sensor axis (e) and the second sensor axis (e) being linearly independent, and a first computational unit () computing a computed pitch angle (θ) based on of the first angular velocity (φ) and the second angular velocity (β). The invention relates also to a method for determining an azimuthal position and azimuthal rotational velocity of the at least one blade relative to the nacelle, the azimuthal position being defined by the rotational motion of the hub relative to the nacelle.